Fire resistant air bar for use in a suspended ceiling structure

ABSTRACT

The fire resistant air bar has high temperature resistant side rails for supporting the fire resistant ceiling tiles of a suspended ceiling, and for supporting an air plenum chamber; has high temperature resistant spacer bars located between the side rails with end tabs thereof extending through slots in the side rails to fasten thereto; has lower temperature melting spacers mounted on the spacer bars between the side rails; and has nested weir channel members located between the spacers, whereby when the spacers weaken or melt due to high temperature of a fire, the spacer bars maintain the spacing of the side rails to continue supporting the ceiling tiles for blocking the passage of the fire through the suspended ceiling.

United States Patent [191 Lambert [451 Apr. 3, 1973 [54] FIRE RESISTANTAIR BAR FOR USE IN A SUSPENDED CEILING STRUCTURE [75] Inventor: RobertR. Lambert, Glcndora, Calif.

[73] Assignee: Air Factors, lnc., Covina, Calif.

[22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,692

[52] US. Cl. ..98/40 D, 52/DIG. 5 [51] rm. Cl. ..F24f 13/06 [58] Fieldof Search ....98/40 D, 40 DL; 52/475, 494,

52/495, DIG. 5

[56] References Cited UNITED STATES PATENTS 3,673,945 7/1972 Rachlin etal ..98l40 D Primary Examiner-William E. Wayner AssistantExaminer-William E. Tapolcai, Jr. AttorneyC. A. Miketta et al.

[57] ABSTRACT The tire resistant air bar has high temperature resistantside rails for supporting the fire resistant ceiling tiles of asuspended ceiling, and for supporting an air plenum chamber; has hightemperature resistant spacer bars located between the side rails withend tabs thereof extending through slots in the side rails to fastenthereto; has lower temperature melting spacers mounted on the spacerbars between the side rails; and has nested weir channel members locatedbetween the spacers, whereby when the spacers weaken or melt due to hightemperature of a fire, the spacer bars maintain the spacing of the siderails to continue supporting the ceiling tiles for blocking the passageof the fire through the suspended ceiling.

9 Claims, 4 Drawing Figures FIRE RESISTANT AIR BAR FOR USE IN ASUSPENDED CEILING STRUCTURE BACKGROUND OF THE INVENTION This inventionrelates to the field of ventilation and more particularly to a fireresistant air bar for use in a fire resistant suspended ceiling.

Modernly, the rooms of buildings and other structures are provided witha decorative and aesthetically pleasing suspended ceiling located belowthe real ceiling of the room. Such suspended ceilings, usually include aframework of main runners and cross runners on which are supportedceiling tiles to separate an attic space from the room below. In thisattic space, typically is located the air conditioning equipment such asair plenum chambers, ducts, etc., for supplying conditioned air to andfor returning air from the room below. In order for the air to pass fromthe attic space to the room below, air bars are located in the frameworkof the suspended ceiling.

Typically, an air bar has a pair of side rails spaced apart by spacersand has air control means, such as nested weirs, located therebetween sothat the air will controllably flow through an air bar to pass throughthe suspended ceiling. The side rails of the air bar additionallysupport the adjacent ceiling tiles of the suspended ceiling to be anintegral part of the suspended ceiling framework.

In many of the buildings, the suspended ceilings are designed to be afire barricade. Such suspended ceilingshave main runners and crossrunners made of a high melting point material and have fire resistantceiling tiles. However, it is not easy to make the air bars of thesuspended ceiling framework out of the high melting point materialbecause of the compliancy of shapes of some of the parts thereof. Theside rails and the nested weirs have relatively simple shapes and so canbe formed of the high melting point material. However, the spacers whichseparate both the side rails and mount the nested weirs, havecomplicated shapes, therefore, the spacers were typically extruded intotheir complicated shape. The high melting point material cannot bereadily and inexpensively extruded in the complicated spacer shapes andso the spacers heretofore have been extruded from lower melting pointmaterial.

If an air bar, having side rails and nested weirs made of high meltingpoint material, were assembled with extruded spacers made of a lowmelting point material, and were included in a fire resistant ceiling,the effectiveness of the ceiling as a fire blockade would be reduced. Incase of a fire, the spacers would soften and possibly melt to drop thenested weirs and to allow the side rails to pivot and drop the fireresistant ceiling tiles, leaving a hole in the suspended ceiling throughwhich the fire could spread. What is needed then is an air bar whichwill maintain its spacing even though the spacers soften or meltentirely.

BRIEF DESCRIPTION OF THE INVENTION Therefore, it is the primary objectof this invention to provide a novel fire resistant air bar for use in afire resistant suspended ceiling.

Other and additional objects of this invention are to provide such anair bar in which high temperature side rails are maintained with theproper spacing when subjected to high temperatures to hold fireresistant ceiling tiles, to provide such an air bar in which hightemperature spacing means are provided for spacing the side rails; toprovide such an air bar in which the spacing means supports the spacers,to provide such an air bar with spacers having cavities to receive thehigh temperature spacing means therein, and to provide such an air barwhich is inexpensive to manufacture, easy to assemble, and effective tomaintain the location of fire resistant ceiling tiles to block thespreading of fire through the ceiling.

Generally stated, the fire resistant air bar for use in a suspendedceiling framework for mounting fire resistant ceiling framework formounting fire resistant ceiling tiles and for mounting an air plenumchamber with an outlet which directs conditioned air through the air barand into the room below, includes a pair of high temperature resistantside rails with flanges for receiving the ceiling tiles, and a pair oflower temperature melting spacers located between the side rails forspacing the side rails to permit the flow of air therebetween, with theimprovement, according to this invention, including the provision ofhigh temperature resistant spacing means positioned between the siderails for maintaining the spacing of the side rails during hightemperatures after the spacers have weakened to enable the side rails tocontinue supporting the fire resistant ceiling tiles. The spacing meansmay be spacer bars made of a high melting point material and with endtabs for extending through slots in the side rails for fastening the twotogether. The spacers may have cavities in which the spacer bars arereceived to locate the spacers between the side rails for supportingnested weirs between the side rails.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary,side-elevational view, partially in section of the fire resistant airbar, according to this invention, mounted in a fire resistant suspendedceiling;

. FIG. 2 is a fragmentary, top-cross-sectional view taken along theplane IIII of FIG. 1;

FIG. 3 is a fragmentary, end-cross-sectional view taken along the planeIII-III of FIG. 1;

FIG. 4 is a perspective view of a spacer bar for use in the fireresistant air bar, according to this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to thedrawings, and particularly to FIGS. 1 and 3, the fire resistant air baris generally denoted by the number 10. The fire resistant air bar 10 isfor mounting an air plenum chamber 11 thereon and for mounting in a fireresistant suspended ceiling 12 so that conditioned air from the airplenum chamber 11 can pass through the suspended ceiling 12 to bediffused throughout a room therebelow. Because it is fire resistant, thesuspended ceiling 12 is constructed of main and cross runners 13 whichhave been folded of heavy gauge sheet metal. Each runner 13 has opposedlower flanges 14, from which a vertical web 15 rises to terminate at ahead ridge 16. The runners 13 divide the ceiling space into generallyrectangular shapes in which are located fire resistant ceiling tiles 17extending between and resting on the flanges 14.

The use of heavy gauge sheet metal runners 13 and fire resistant ceilingtiles 17 provides a barrier to the spreading of a fire from the roombelow to the attic space above the suspended ceiling 12. This barrierhas heretofore been broken by the use of prior art air bars in thesuspended ceiling 12. Such prior art bars melt, upon being subjected tohigh temperatures, to fall themselves or to drop the ceiling tiles 17supported thereby. The falling of the air bars or the ceiling tiles 17would cause an opening through the suspended ceiling barrier throughwhich the fire could spread. The fire resistant air bar 10, according tothis invention is so constructed that when the bar is subjected to thehigh temperatures of a fire, the bar 10 will continue to act as anintegral part of the ceiling 12 to maintain the ceiling 12 as a firebarrier.

Generally stated, the fire resistant air bar 10 includes hightemperature resistant side rails-20 having flanges 23 for receiving andsupporting ceiling tiles 17, lower temperature melting spacers 30,either end spacers 31 or intermediate spacers 41, located between theside rails 20 for spacing the side rails 20 to permit the flow of airtherethrough, and high temperature resistant spacer means 50 such asspacer bars 51 positioned between the side rails 20 for maintaining thespacing of the side rails 20 during high temperatures after the spacers30 have weakened to enable the side rails 20 to continue supporting thefire resistant ceiling tiles 17. The air bar is completed by air controlmeans 60 such as nested weir means 61, extractors 65 and blank offs 70.

Referring now primarily to FIG. 3 the side rails 20 of the air bar 10are formed of heavy gauge sheet metal such as steel, or other suitablemetal with a high melting temperature. The side rails 20, each have sidewalls 21 with an upper inwardly extending lip 22 for mounting the airplenum chamber 11. A reverse bend is formed in the central portion ofthe side wall 21 to provide a central outwardly extending flange 23 forreceiving and supporting the adjacent edges of the ceiling tiles 17. Thelower edge of the side wall 21 is bent inwardly to provide a lowerinwardly extending flange 24 for diffusing the air that passes throughthe air bar 10. The ends of the side walls 21 have hooks 25 formedtherein adjacent the upper edge thereof for hooking over the head ridges16 of adjacent means runners 13 for mounting the air bar 10 in thesuspended ceiling 12. Selected side walls 21 will have slots 27 formedtherein which are closed by knock out plates 28 which will, when opened,provide an air return through the suspended ceiling 12. The side rails20 are not completely ready to be spaced by the spacers 30.

The spacers 30 are for spacing the side rails 20 to permit the flow ofair therethrough and for mounting the air control means 60. Because ofthe complicated shape of the spacers 30, they cannot be inexpensivelymade of heavy gauge sheet metal which has a high melting point but havebeen extruded ofa metal such as aluminum. Such metals along with beingextrudable, also have a low melting temperature. Therefore, the spacers30 can only be depended upon to space the side rails 20 during normalroom temperatures.

The spacers, illustratively shown are of two types, end spacers 31 andintermediate spacers 41. As best seen in FIG. 1, each end spacer 31 hasa vertical web 32 with an inverted channel 33 formed in the upper endthereof for receiving a block 34 of rubber or other sealing matelial.Below the channel 33, the web 32 defines an open sided circular cavity35 for receiving sheet metal screws. Vertically spaced upper and lowerflanges 36 and 37 extend inwardly from the web 32 directly below thecavity 35. Below the lower flange 36, the web 32 is bent outwardlybefore returning to the vertical to have a foot flange 38 extendoutwardly therefrom for resting o the flanges 14 of an adjacent runner13. The lower edge of the web 32 is folded inwardly to provide alowermost flange 39 which will engage the upper side of the lowerinwardly extending flange 24 of the side rails 20 to provide stiffeningthereto.

The intermediate spacer 41 is shown in hidden lines in FIG. 1 and has aweb 42. The web 42 has on the upper edge thereof an inverted channel 43again with a block 34 located therein. Below the channel 43, the web 42defines an open sided circular cavity 44 for receiving sheet metalscrews. Oppositely extending vertically spaced upper and lower flanges45 and 46 are formed in the web 42 below the cavity 44 to complete theintermediate spacer 41, ready to be mounted between the side rails 20 bythe spacer means 50.

The spacer means 50 are high temperature resistant and are forpositioning between the side rails for maintaining the spacing of theside rails during high tem peratures after the spacers 30 have weakened.As best seen in FIG. 4, the illustrated spacer means 50 are spacer bars51 of generally rectangular shape. Each spacer bar 51 is formed out of asuitable high temperature melting material such as steel or othersuitable metal. Each spacer bar 51 has end surfaces 52 which are spacedequal to the spacing of the inside surfaces of the side rails 20. Eachspacer bar 51 is for location in a cavity 53 in a respective spacer 31or 41, which is defined between the upper and lower flanges 36 and 37 or45 and 46 by opposed ridges 54 provided therein. The spacer bars 51, solocated, support the spacers 41 and 31 and are ready to be secured tothe side rails 20 by fastening means 55.

The fastening means 55 are for fastening the bars 51 to and between theside rails 20. In the illustrated embodiment, the fastening means 55includes the provision of parallel tabs 56 extending outwardly from theend surfaces 52 of each spacer bar 51. The fastening means 55 alsoincludes the provision of matingly, vertically spaced slots57 in theside rails 20 at the location of the spacer bars 51. As best seen inFIG. 2, the tabs 56 extend through the slots 57 to be bent over the siderails 20 to thereby mount the spacers 31 and 41 between the side rails20 for receiving the air control means 60.

The air control means 60 are provided between the side rails 20 forregulating the flow of conditioned air between the side rails. Theillustrated air control means 60 are nested weir means 61, extractors65, and blank offs 70. The nested weir means 60 were first disclosed inmy US. Pat. No. 3,411,425 as including an upper channel member 62inverted and inserted into a lower channel member 63. The channelmembers 62 and 63, thus nested, are inserted between the upper and lowerflanges 36 and 37, of the end spacers 31 and between the upper and lowerflanges 45 and 46 of the interthereof.

mediate spacers 41 to extend therebetween. The channel members 62 and 63may be extended or contracted to regulate the flow of conditioned airbetween the side rails 20.

The extractors 65 are for extracting a measured amount of air from theair plenum chamber ll and directing it down between the side rails 20.As best seen in the left side of FIG. 1, the extractors 65 are plates 66with vanes 67 upstanding therefrom leaving holes 68. The plates 66 asbest seen in FIG. 3, slid under the lips 22 of the side rails 20 on theblocks 34 to seal thereagainst. The vanes 67 deflect the air in theplenum chamber 11 down through the holes 68 between the side rails 20 tobe diffused by the lower flanges 24 When air passage from the air plenumchamber 11 between the side rails 20 is not desired, blank-offs 70 areprovided for preventing such air flow. The blankoffs 70 are plates 71again slid under the lips 22 of the side rails 20 on the rubber blocks34 to be sealed thereby. Usually where blank offs 70 are provided, theknock out plates 27 are removed to permit the return of air from theroom through the suspended ceiling 12 into the attic space thereabove.

It is contemplated that the fire resistant air bar will be sold andinstalled in the fire resistant suspended ceiling 12 as a unit. The unitis assembled by inserting the spacer bars 51 into the cavities 53in thespacers 31, 34. The channel members 62 and 63 are nested and inserted inbetween the flanges 36, 37, and 46, 45. The blocks 34 are inserted inthe channels 33 and 24 or the spacers 31, 41 and extractors 65 and/orblank offs may be positioned thereon. The side rails are slid onto thetabs 56 of the spacer bars 51 and the spacer bars 51 bent over to securethe air bar together ready to be hung in a suspended ceiling 12. Sheetmetal screws may be pushed through the side rails 20-to be turned intothe cavities 35,44 to additionally secure the side rails 20 to the endspacers 31 and intermediate spacers 41.

The air bar 10 is hung by hooks 25 over the main runners 13 to becentrally located between an adjacent pair of cross runners 13. An airplenum chamber is mounted to the air bar by inserting the outlet wallsthereof between the lips 22 of the side rails 20. Ceiling tiles 17 areinserted between the flanges to extend between the cross runners l3 andthe air bar 11 to be supported thereby, to complete the fire resistantceiling l l.

In the event of a fire in the room below the fire resistant suspendedceiling 12, the heat produced by the fire may be sufficient to weaken ormelt the spacer 31 and 41 to drop the nested channel members 62 and 63,the extractors 65, and blank offs 70 onto the flanges 24 of the air bar10 to close the space between the side rails 20 thereof. Yet the meltingof the spacers 31 and 41 will not allow the side rails 20 to pivot anddrop the ceiling tile 17 because the spacer bars 51 will maintain thespacing of the side rails 20 to enable the side'rails 20 of the fireresistant air bar 10 to continue supporting the fire resistant ceilingtile 17. The fire resistant ceiling tile 17 in the suspended ceiling 12will help to confine the fire therebelow and will help prevent thespreading of the fire to the attic space above the suspended ceiling.

1 claim:

1. A fire resistant air bar for use in a suspended ceiling framework formounting fire resistant ceiling tiles and for mounting an air plenumchamber with an outlet which directs conditioned air through the air barand into the room below, said air bar having a pair of high temperatureresistant side rails with flanges for receiving the ceiling tiles, and apair of lower temperaturemelting spacers located between the side railsfor spacing the side rails to permit the flow of air therebetween, theimprovement comprising the provision of:

high temperature resistant spacing means positioned between the siderails for maintaining the spacing of the side rails during hightemperatures after the spacers have weakened to enable the side rails tocontinue supporting the fire resistant ceiling tiles.

2. The invention as in claim 1 wherein the high temperature resistantspacing means includes at least a pair of spacer bars made of a materialhaving a high melting point, said bars having end surfaces spacedcorrespondingly to the spacing between the inner surfaces of the siderails to be located therebetween.

3. The invention as in claim 2 wherein fastening means is provided forfastening the bars to and between the side rails.

4. The invention as in claim 3 wherein the fastening means includes theprovision of tabs protruding from the end surfaces of the bars and theprovision of slots in the side rails, said slots receiving said tabs tofasten the bars between the side rails.

5. The invention as in claim 2 wherein the spacers are provided withsuitable shaped cavities for receiving the spacer bars therein, saidspacer bars being located in the cavities to be joined to the spacers.

6. The invention as in claim 1 wherein air control means is providedbetween the side rails for regulating the flow of conditioned airtherebetween, wherein the spacers are formed to receive and mount theair control means and wherein said spacing means mounts the spacersbetween the side rails.

7. The invention as in claim 6 wherein the spacing means includes a pairof spacer bars, and means for fastening the spacer bars to the siderails, and wherein the spacers includes a'web and means for mounting theweb to the spacer bars.

8. The invention as in claim 7 wherein the means for fastening includesthe provision of end tabs on the bars and slots in the side rails forreceiving the end tabs to mount the spacing bars.

9. The invention as in claim 7 wherein the mounting means includes theprovision of a spacing bar receiving cavity in each web, said spacer barbeing positioned in the cavity to mount the web thereto.

1. A fire resistant air bar for use in a suspended ceiling framework formounting fire resistant ceiling tiles and for mounting an air plenumchamber with an outlet which directs conditioned air through the air barand into the room below, said air bar having a pair of high temperatureresistant side rails with flanges for receiving the ceiling tiles, and apair of lower temperature-melting spacers located between the side railsfor spacing the side rails to permit the flow of air therebetween, theimprovement comprising the provision of: high temperature resistantspacing means positioned between the side rails for maintaining thespacing of the side rails during high temperatures after the spacershave weakened to enable the side rails to continue supporting the fireresistant ceiling tiles.
 2. The invention as in claim 1 wherein the hightemperature resistant spacing means includes at least a pair of spacerbars made of a material having a high melting point, said bars havingend surfaces spaced correspondingly to the spacing between the innersurfaces of the side rails to be located therebetween.
 3. The inventionas in claim 2 wherein fastening means is provided for fastening the barsto and between the side rails.
 4. The invention as in claim 3 whereinthe fastening means includes the provision of tabs protruding from theend surfaces of the bars and the provision of slots in the side rails,said slots receiving said tabs to fasten the bars between the siderails.
 5. The invention as in claim 2 wherein the spacers are providedwith suitable shaped cavities for receiving the spacer bars therein,said spacer bars being located in the cavities to be joined to thespacers.
 6. The invention as in claim 1 wherein air control means isprovided between the side rails for regulating the flow of conditionedair therebetween, wherein the spacers are formed to receive and mountthe air control means and wherein said spacing means mounts the spacersbetween the side rails.
 7. The invention as in claim 6 wherein thespacing means includes a pair of spacer bars, and means for fasteningthe spacer bars to the side rails, and wherein the spacers includes aweb and means for mounting the web to the spacer bars.
 8. The inventionas in claim 7 wherein The means for fastening includes the provision ofend tabs on the bars and slots in the side rails for receiving the endtabs to mount the spacing bars.
 9. The invention as in claim 7 whereinthe mounting means includes the provision of a spacing bar receivingcavity in each web, said spacer bar being positioned in the cavity tomount the web thereto.